Gas container valve

ABSTRACT

The gas container valve has a valve body (4) with a detachably mounted valve head (5) which by means of a valve spring (6) is pressed against a seat (3) of a bushing (7) screwed into the housing (2) of the gas container valve. The valve body has at its other end a second valve head (8) which when the bushing (7) is unscrewed is pressed against a second valve seat (9) of the valve housing 2 by the valve spring. Thereby, it becomes possible to replace/repair the first valve seat (3) and/or the first valve head (5), while the gas container valve is mounted on a gas container containing gas under pressure.

The invention relates to a gas container valve for a container forliquified gas comprising a valve housing with a detachably mountedbushing with a valve seat, an elongate valve body which is displaceablein a bore in the valve housing, said valve body comprising a valve head,a valve spring biassing the valve body against the valve seat in theoutflow direction of the gas, and a second valve seat and valve headplaced upstream of the valve seat and the valve head.

A gas container valve of this type is known from EP-A1-0 018 121corresponding to DK Patent Application No. 1516/79. In this known gascontainer valve the valve seat and the valve head may be removed forreplacement or repair purposes without any need for emptying thecontainer of gas, as the container may be closed by means of a secondvalve positioned up-stream of the first valve, said second valve beingin this case manually operated. This gas container valve suffers fromthe substantial drawback that it is expensive to manufacture and isliable to damage during handling of the container for liquified gas.Furthermore, it has the drawback that the detachably mounted bushing, inwhich the valve seat is located, also contains the valve body with valvespring and abutment therefor, which for a replacement of the valve headentails dismantling of said parts with a subsequent reassembling, whichis labour-consuming.

EP-A2-0 098 914 discloses a double seal valve for filling pressurizedtanks. The valve contains two separate valve units each having a valveseat, a valve head and a valve spring. The valve unit adjacent to thetank is arranged to open after the other valve unit opens and to closebefore the other valve unit closes.

DK Patent No. 112.696 discloses a gas container valve, in which twodetachable bushings are placed one after the other, each having a valveaggregate comprising valve seat, valve head, valve spring, and abutmentfor the valve spring. This gas container valve is expensive tomanufacture and requires like the aforementioned gas container valvemuch labour in connection with dismantling and replacement of damagedvalve parts.

U.S. Pat. No. 4,120,314 discloses a hydraulic activation valve, in whichvalve seat, valve head, valve spindle and valve spring are contained ina unit, which may be screwed into the valve aggregate. The individualparts are, however, assembled in the bushing in such a way that theycannot be replaced, and it is necessary to discard all parts if thevalve becomes leaky.

It is the object of the invention to provide a gas container valve whichallows the repair of a leaky gas container valve, without the gascontainer having to be emptied first of gas, and in which the valve doesnot suffer from the above-mentioned drawbacks.

This object is met according to the invention by a valve of the typestated by way of introduction, said valve being characteristic in thatthe first valve head is detachably mounted on the valve body, that thesecond valve head is mounted on the valve body, that the valve spring ispositioned between the first and the second valve heads, one endengaging an abutment in the bore of the valve housing and the other endengaging the valve body that the valve unit formed by the second valveseat and the second valve head is open when the bushing is mounted inthe valve housing, and in that the valve spring brings the second valvehead to sealing contact with the second valve seat, when the bushing hasbeen dismantled.

Dismantling of the bushing results in the valve body being free todisplace itself in the outflow direction of the gas under bias of thevalve spring, until the second valve head at the end of the valve bodyfacing the gas container abuts against its valve seat and consequentlyimpedes gas in the container from flowing out. It is then possible toreplace the first valve head and/or the bushing and to assemble the gascontainer valve again without having to empty the container of gasfirst. The first valve head is detachably mounted on the valve body andby dismantling the detachable bushing quick access for repair orexchange of the valve seat in the bushing and the valve head isattained. The valve body with valve spring, however, remains in thehousing of the gas container valve, and the valve spring pulls thesecond valve head into abutment against the second valve seat, the gasin the container being thus prevented from streaming out. Thus, only theparts to be replaced are removed, and the task of dismantling is reducedto a minimum.

In a preferred embodiment the valve body comprises an upper partcarrying the first valve head and being provided with means for guidingthe valve body in the bore, and a lower part carrying the second valvehead. This makes it possible to mount each of the two parts of the valvebody from their respective ends of the valve housing and to assemblethem for instance by screwing together or by soldering.

In a particularly preferred embodiment of the invention the upper andlower parts of the valve body are connected by means of a snap lock,which makes the assembly particularly simple, the two parts just havingto snap into each other, whereby more complicated operations, like forinstance the above-mentioned screwing together or welding, are avoided.

Another embodiment of the invention is characteristic in that the valvebody is a unit and that the biggest cross-section of the second valvehead is smaller than the opening defined by the second valve seat andcarries a resilient sealing, the outer periphery of which, seen in aplane parallel to the second valve seat, is bigger, when in use, thanthe outer periphery of said opening. Hereby, a particularly simplemanufacture of the valve body is attained, and if the sealing forinstance consists of a resilient ring which is to be placed in a groovein the second valve head, the assembly work is reduced to running thevalve body through the valve housing from one end and then to snappingthe O-ring into the groove from the other end of valve housing. Theassembly work may be further simplified in that the dimension of thegroove and the resiliency of the sealing are chosen such that the forceneeded for pressing the valve body with mounted sealing through theopening defined by the valve body is substantially bigger than the forceexerted by the gas in a gas container on the other valve head againstits seat, when the bushing has been removed, whereby it is ensured thatthe valve head cannot be pressed out again by the gas. By such asolution the assembly is reduced to just inserting the valve body fromone end of the valve housing and pressing it through the opening of thesecond valve seat.

In a third embodiment the valve body may have means for guiding thevalve body in the opening defined by the second valve seat. This has theeffect that the valve is guided more securely during its movement, theguiding means contributing simultaneously to impart a bigger rigidity tothe valve body, which contributes to safeguarding the valve body againstdamage during the handling before or during the assembly.

In a preferred embodiment of the gas container valve according to theinvention the abutment for the first end of the valve spring is anannular shoulder in the bore of the valve housing and carries the secondvalve seat. This combination of valve seat and abutment for the valvespring simplifies the manufacture of the gas container valve and makesit less expensive.

The invention will now be explained in detail in the following by meansof an embodiment and with reference to the drawing, in which

FIG. 1 is a longitudinal sectional view of a gas container valveaccording to the invention, the first valve head being in close abutmentagainst its seat,

FIG. 2 a cross-sectional view along line II--II in FIG. 1,

FIG. 3 is a longitudinal sectional view of the valve housing in FIG. 1,the bushing and the first valve head being shown in a dismantled state,and the second valve head in close abutment against its seat,

FIG. 4 is a longitudinal sectional view of a valve housing and a valvebody in two parts for assembly by a snap lock, and

FIG. 5 is a sectional view of a valve housing and an integral valve bodyand associated sealing.

The gas container valve 1 shown in the drawing has a housing 2 with acentral bore 14 and an outer, conical thread 15 for the screwing down ofthe gas valve in the outlet of a gas container. In the other end of thecontainer a bushing has been screwed on, said bushing carrying a valveseat 3. The bushing has an O-ring 16 for sealing the joint against thevalve housing 1. Internally, the bushing is provided with a hexagonalhole 11 allowing an Allen key to be used for the dismantling of thebushing.

In the bore 14 of the valve housing 2 a valve body 4 is provided, saidvalve body carrying four wings 18 which guide the valve body during itsmovement in the bore. A valve spring 6 has been inserted between thevalve guides 18 and an annular projection 10 in the bore 14, said valvespring acting on the valve body in the direction towards the valve seat3. A valve head 5 carried by the valve body 4 is, as will be best seenfrom FIG. 2, provided with a pin 12 which fits loosely in a central bore13 in the valve body, and a sealing 20 providing a tight sealing againstthe valve seat 3. The valve body 4 comprises in this case an upper part4a and a lower part 4b assembled by means of soldering.

The annular projection 10 in the bore 14 of the valve housing forms avalve seat 9 for a second valve head 8 which is integral with the end ofthe valve body 4. The valve head 8 carries a sealing 21 for providing atight sealing against the valve seat 9.

As can be seen from FIGS. 1 and 2, the distance between the O-ring 16and the top of the valve housing 2, when the bushing 7 is in the mountedposition, is larger than the distance between the sealing side of seal21 and the second valve seat 9. As a result, as the bushing 7 is removedby unscrewing, the sealing 21 of the second sealing valve head 8 sealsagainst the second valve seat 9 before O-ring 16 is moved out of sealingengagement with the wall of the bore in the top of the valve housing 2.Also, the sealng between the seal 20 of the first sealing valve head 5and the first valve seat 3 will be maintained due to the action of thespring 6 until the sealing 21 of the second sealing valve head 8 sealsagainst the second valve seat 9. Conversely, when the detachably mountedbushing 7 is mounted, the gas passage between the bushing and the borein the valve housing 2 is sealed by the O-ring 16, and the gas passagethrough the first valve seat 3 is sealed by the first sealing valve head3 before the second sealing valve head 8 is opened.

The valve body shown in FIG. 4 consists of two parts 4a,4b carrying thefemale and the male part of a snap lock connection. The snap lockconnection of the lower part 4b comprises a collar 27 and a truncatedcone 25, the large end base of which forms a shoulder 26. The snap lockconnection of the upper part 4a is established by a narrowing 28 of thebore 13, where the transition between the narrowing and the bore formsan internal shoulder 29. The valve body is assembled by introducing thetruncated cone 25 of part 4b into the narrowing 28 until collar 27 abutsagainst the under side of part 4a and the rim of the base 26 abutsagainst the shoulder 29.

The valve body 4 shown in FIG. 5 is integral and has a head 8a whichextends through the opening 9a of the valve housing 2. The valve body 4has a set of wings 18 for guidance in the bore 14 of the valve housingand another set of wings 30 for guidance in the opening 9a. The valvehead 8a has a groove 31 for receiving a sealing 21, here shown as anO-ring.

When repairing a leaky gas container valve 2 the bushing 7 is screwedout first from the valve housing 2, following which the valve head 5 istaken out. Simultaneously therewith the valve spring 6 biasses valvehead 8 towards its seat 9 and thereby prevents the gas in the containerfrom flowing out. Depending on the kind of leak, a new valve head 5and/or a new bushing is then mounted.

During the first part of the screwing down of the bushing 7 the secondvalve head 8 closes for the gas stream, until the valve seat 3 of thebushing abuts the first valve head 5, which then takes over the closing.At the same time valve 8,9 is opened at the bottom end of valve body 4as the bushing 7 is screwed all the way down.

I claim:
 1. A gas container valve (1) for a container for liquified gascomprising a valve housing (2) with a detachably mounted bushing (7)with a first valve seat (3), an elongate valve body (4) which isdisplaceable in a bore (14) in the valve housing, said valve bodycomprising a first sealing valve head (5), a valve spring (6) biasingthe first sealing valve head into flow obturating engagement against thefirst valve seat in the outflow direction of the gas, and a second valveseat (9) and a second sealing valve head (8) placed upstream of thefirst valve seat (3) and the first sealing valve head (5), characterizedin that the first sealing valve head (5) is detachably mounted on thevalve body (4), that the second sealing valve head (8) is mounted on thevalve body (4), that the valve spring (6) is positioned between thefirst (5) and the second (8) sealing valve heads, one end of the valvespring engaging an abutment (10) in the bore (14) of the valve housing(1) and the other end of the valve spring engaging the valve body (4),that the valve unit formed by the second valve seat (9) and the secondsealing valve head (8) is open when the bushing (7) is mounted in thevalve housing (2), and in that the valve spring (6) brings the secondsealing valve head (8) to flow obturating sealing contact with thesecond valve seat (9) when the bushing (7) has been dismantled.
 2. A gascontainer valve according to claim 1, characterized in that the valvebody (4) comprises an upper part (4a) carrying the first sealing valvehead (5) and being provided with means (18) for guiding the valve body(4) in the bore (14) and a lower part (4b) carrying the second sealingvalve head (8).
 3. A gas container valve according to claim 2,characterized in that the upper and lower parts (4a and 4b) of the valvebody (4) are connected by means of a snap lock.
 4. A gas container valveaccording to claim 1, characterized in that the valve body (4) is a unitand that the biggest cross-section of the second sealing valve head (8a)is smaller than the opening (9a) defined by the second valve seat (9)and carries a resilient sealing (21), the outer periphery of which, seenin a plane parallel to the second valve seat (9), is bigger when in usethan the outer periphery of said opening (9a).
 5. A gas container valveaccording to claim 1 characterized in that the valve body (4) has means(30) for guiding the valve body (4) in the opening (9a) defined by thesecond valve seat (9).
 6. A gas container valve according to claim 1characterized in that the abutment (10) for the first end of the valvespring (6) is an annular projection (10) in the bore (14) of the valvehousing (2) and carries the second valve seat (9).
 7. A gas containervalve according to claim 2, characterized in that the valve body (4) hasmeans (30) for guiding the valve body (4) in the opening (9a) defined bythe second valve seat (9).
 8. A gas container valve according to claim3, characterized in that the valve body (4) has means (30) for guidingthe valve body (4) in the opening (9a) defined by the second valve seat(9).
 9. A gas container valve according to claim 4, characterized inthat the valve body (4) has means (30) for guiding the valve body (4) inthe opening (9a) defined by the second valve seat (9).
 10. A gascontainer valve according to claim 2, characterized in that the abutment(10) for the first end of the valve spring (6) is an annular projection(10) in the bore (14) of the valve housing (2) and carries the secondvalve seat (9).
 11. A gas container valve according to claim 3,characterized in that the abutment (10) for the first end of the valvespring (6) is an annular projection (10) in the bore (14) of the valvehousing (2) and carries the second valve seat (9).
 12. A gas containervalve according to claim 4, characterized in that the abutment (10) forthe first end of the valve spring (6) is an annular projection (10) inthe bore (14) of the valve housing (2) and carries the second valve seat(9).
 13. A gas container valve according to claim 5, characterized inthat the abutment (10) for the first end of the valve spring (6) is anannular projection (10) in the bore (14) of the valve housing (2) andcarries the second valve seat (9).
 14. A gas container valve accordingto claim 7, characterized in that the abutment (10) for the first end ofthe valve spring (6) is an annular projection (10) in the bore (14) ofthe valve housing (2) and carries the second valve seat (9).
 15. A gascontainer valve according to claim 8, characterized in that the abutment(10) for the first end of the valve spring (6) is an annular projection(10) in the bore (14) of the valve housing (2) and carries the secondvalve seat (9).
 16. A gas container valve according to claim 9,characterized in that the abutment (10) for the first end of the valvespring (6) is an annular projection (10) in the bore (14) of the valvehousing (2) and carries the second valve seat (9).
 17. A gas containervalve according to claim 1, characterized in that the valve spring (6)is the sole spring of the valve.
 18. A gas container valve (1) for acontainer for liquified gas comprising a valve housing (2) with adetachably mounted bushing (7) with a first valve seat (3), a valve body(4) which is displaceable in a bore (14) in the valve housing, saidvalve body comprising a first sealing valve head (5) , a valve spring(6) biasing the first sealing valve head into flow obturating engagementagainst the first valve seat in the outflow direction of the gas, and asecond valve seat (9) and a second sealing valve head (8) placedupstream of the first valve seat (3) and the first sealing valve head(5), characterized in that the first sealing valve head (5) isdetachably mounted on the valve body (4), that the second sealing valvehead (8) is mounted on the valve body (4), that the valve unit formed bythe second valve seat (9) and the second sealing valve head (8) is openwhen the bushing (7) is mounted in the valve housing (2), and in thatthe valve spring (6) brings the second sealing valve head (8) to flowobturating sealing contact with the second valve seat (8) when thebushing (7) has been dismantled,wherein the valve further comprisesmeans (16) for providing a seal between the detachably mounted bushingand the valve housing (2) before the second sealing valve head (8) isopened.
 19. A gas container valve according to claim 18, wherein saidmeans for providing a seal comprises a seal (16) mounted on thedetachably mounted bushing (7).
 20. A gas container valve according toclaim 19, wherein the bore has an outer end and receives the detachablymounted bushing (7), the bore has a wall sealingly engaged by the seal(16), and said outer end of the bore is larger than the distance betweenthe sealing side of the seal (21) on the second sealing valve head (8)and the second valve seat (9), when the detachable bushing (7) ismounted in said bore.